Problem: Kevin is 5 times as old as Ishaan and is also 12 years older than Ishaan. How old is Ishaan?
Solution: We can use the given information to write down two equations that describe the ages of Kevin and Ishaan. Let Kevin's current age be $k$ and Ishaan's current age be $i$ $k = 5i$ $k = i + 12$ Now we have two independent equations, and we can solve for our two unknowns. Since we are looking for $i$ , and both of our equations have $k$ alone on one side, this is a convenient time to use elimination. Subtracting the second equation from the first equation, we get: $0 =$ $5i$ $-$ $ (i + 12)$ which combines the information about $i$ from both of our original equations. Solving for $i$ , we get: $4 i = 12$ $i = 3$.